The face is not created by aliens and here are a few reasons why. It was a mesa, or maybe even a shadow. but aliens is not a logical reason for this face to exisist on mars.

First, A mesa, a mesa is a very common landform found around the American West. Even so there is one in the Snake River Plain of Idaho, USA. Which is a lava dome that takes the form of an isolated mesa about the same height as the face on mars. If something on the earth can have a mesa about or the same height had the face on mars it is very likely that it was a mesa.

Secondly, shadows We all knows that shadows can be very deceiving just like in this instance. A shadow could have been reflecting off the viking 1 while it was taking this photo of the "Face", or maybe the shadows were from a bigger land form. that was infront, behind, or on the sides casting a shadow onto this mesa.

All in all, From these facts you can conclude that this was a natural landform and not some type of alien thing. If you still do not believe that it was natural. Another spaceship went into space and found the "Face" and took a very detailed picture and there were no markings or signs of aliens.               